Neighbor discovery in a wireless system

Abstract

Beacons may be grouped to facilitate neighbor discovery in a wireless network. For example, neighboring access devices such as IEEE 802.11 access points may cooperate to transmit beacons in a group. In this way, a wireless device seeking to discover the neighboring access devices may scan for the beacons for a shorter period of time. An indication may be provided to enable a wireless device to more efficiently scan the beacons. For example, the indication may indicate the channel the wireless device should scan to receive the next beacon that is to be transmitted. In addition, the indication may include information relating to the transmission time of the next beacon. Other aspects, embodiments, and features are also claimed and described.

What is claimed is: 
     
       1. A method of providing beacons by an access point, comprising:
 cooperating, with at least one other access point, to determine when to transmit beacons of associated time division multiplexed wireless networks, wherein each beacon comprises an identifier of one of the time division multiplexed wireless networks; 
 maintaining at least one defined spacing between successive transmissions of the beacons; and 
 transmitting the beacons of at least one of the networks. 
 
     
     
       2. The method of  claim 1 , wherein the access points transmit the beacons so that the beacons are not overlapping in time. 
     
     
       3. The method of  claim 1 , wherein all of the beacons, to be sent by the access points using a given channel, are sent consecutively in time. 
     
     
       4. The method of  claim 1 , wherein, when a next beacon and a previous beacon are sent on different channels, the at least one defined spacing is more than a channel switching time of a radio of a wireless device that is adapted to receive the next beacon and the previous beacon. 
     
     
       5. The method of  claim 1 , wherein the access points repetitively transmit a group of the beacons associated with at least a portion of the wireless networks;
 each beacon in the group of beacons is associated with a different one of the wireless networks; and 
 the access points transmit the beacons in each group within a defined period of time. 
 
     
     
       6. The method of  claim 5 , wherein the defined period of time is less than a beacon interval. 
     
     
       7. The method of  claim 1 , wherein the access points cooperate to successively transmit, in turn, one of the beacons associated with each of the wireless networks. 
     
     
       8. The method of  claim 1 , wherein cooperating comprises establishing beacon transmission times to:
 reduce a total time used to transmit a set of non-time overlapping beacons; and 
 provide reduced beacon scan time and total search time for a wireless device that is adapted to receive the beacons. 
 
     
     
       9. The method of  claim 1 , further comprising:
 determining a beacon transmission time of one of the access points; and 
 using the beacon transmission time to establish target beacon transmit times for a set of the access points in a given geographical area. 
 
     
     
       10. The method of  claim 1 , further comprising generating an indication regarding transmission of at least one next beacon by the at least one other access point. 
     
     
       11. The method of  claim 10 , wherein the indication identifies at least one channel or at least one time upon which the at least one next beacon will be transmitted. 
     
     
       12. An access point apparatus for providing beacons, comprising:
 a controller adapted to cooperate, with at least one other access point, to determine when to transmit beacons of associated time division multiplexed wireless networks, and to maintain at least one defined spacing between successive transmissions of the beacons, wherein each beacon comprises an identifier of one of the time division multiplexed wireless networks; and 
 a transmitter for transmitting the beacons of at least one of the networks. 
 
     
     
       13. The apparatus of  claim 12 , wherein the access points transmit the beacons so that the beacons are not overlapping in time. 
     
     
       14. The apparatus of  claim 12 , wherein all of the beacons, to be sent by the access points using a given channel, are sent consecutively. 
     
     
       15. The apparatus of  claim 12 , wherein the controller is further adapted to cooperate to establish transmission times for the beacons to:
 reduce a total time used to transmit a set of non-time overlapping beacons; and 
 provide reduced beacon scan time and total search time for a wireless device that is adapted to receive the beacons. 
 
     
     
       16. The apparatus of  claim 12 , wherein the controller is further adapted to:
 determine a beacon transmission time of one of the access points; and 
 use the beacon transmission time to establish target beacon transmit times for a set of the access points in a given geographical area. 
 
     
     
       17. The apparatus of  claim 12 , further comprising an indication generator adapted to generate an indication regarding transmission of at least one next beacon by the at least one other access point. 
     
     
       18. A computer program product for an access point comprising:
 a non-transitory computer-readable medium comprising code for causing at least one computer to:
 cooperate, with at least one other access point, to determine when to transmit beacons of associated time division multiplexed wireless networks, and to maintain at least one defined spacing between successive transmissions of the beacons, wherein each beacon comprises an identifier of one of the time division multiplexed wireless networks; and 
 transmit the beacons of at least one of the networks. 
 
 
     
     
       19. The computer program product of  claim 18 , wherein the access points transmit the beacons so that the beacons are not overlapping in time. 
     
     
       20. The computer program product of  claim 18 , wherein all of the beacons, to be sent by the access points using a given channel, are sent consecutively. 
     
     
       21. The computer program product of  claim 18 , wherein the non-transitory computer-readable medium further comprises code for causing the at least one computer to establish beacon transmission times to:
 reduce a total time used to transmit a set of non-time overlapping beacons; and 
 provide reduced beacon scan time and total search time for a wireless device that is adapted to receive the beacons. 
 
     
     
       22. The computer program product of  claim 18 , wherein the non-transitory computer-readable medium further comprises code for causing the at least one computer to:
 determine a beacon transmission time of one of the access points; and 
 use the beacon transmission time to establish target beacon transmit times for a set of the access points in a given geographical area. 
 
     
     
       23. The computer program product of  claim 18 , wherein the non-transitory computer-readable medium further comprises code for causing the at least one computer to generate an indication regarding transmission of at least one next beacon by the at least one other access point.